[rules-dev] Drools in Google App Engine
Geoffrey De Smet
ge0ffrey.spam at gmail.com
Fri May 15 04:16:51 EDT 2009
I am not surprised that File.exists() fails, but why does
getClass().getResourceAsStream() fail?
In Applets, the latter should work:
http://java.sun.com/docs/books/tutorial/uiswing/components/applet.html
chapter Using Images in a Swing Applet.
Because getClass().getResourceAsStream() only looks in the classpath,
I see not reason that Google App Engine would block it.
With kind regards,
Geoffrey De Smet
Paul Browne schreef:
> Geoffrey,
>
> The stack exception below is Drools looking for the conf file *before*
> it even looks for the DRL file. However *any* file IO is blocked - so
> even it Drools got past the File.exists(), it's likely to throw another
> SecurityException at the getClass().getResourceAsStream for the DRL file.
>
> I say 'likely' as 3 months ago I was trying to get version 4 of Drools
> running in an Applet environment (has similar security constraints), and
> worked my way through the source code to resolve the security
> exceptions. In that case, getClass().getResourceAsStream was blocked.
>
> Any suggestions?
>
> Thanks
>
> Paul
>
>
>
>
> On Wed, May 13, 2009 at 4:51 PM, Geoffrey De Smet
> <ge0ffrey.spam at gmail.com <mailto:ge0ffrey.spam at gmail.com>> wrote:
>
> Does this File.exists() usage occur even if your DRL is a classpath
> resource and fetched with getClass().getResourceAsStream()?
>
> With kind regards,
> Geoffrey De Smet
>
>
> Paul Browne schreef:
>
> Folks,
>
> Are there any plans to tweak Drools to allow it to run in a
> security constrained environment such as Google App Engine or
> Applets? I know some of the other JBoss.org projects have this
> on the 'todo' list.
>
> When I try to load a simple web application using drools into
> the Google App Engine, I get the error below.The app itself is
> the sample 8 from the following web page, but tweaked according
> to the Google 'howto' to get it up and running in the app
> engine; http://code.google.com/p/red-piranha/
>
> My understanding of the problem is that drools is using File
> access to check if the configuration file exists the first time
> it is run. This is constrained in App Engine - just like the
> J2EE spec says it should be (although most other app servers
> allow you to get away with this!). I know that if I tweak the
> source code there will be other points where similar file access
> is required.
>
> While not trivial, would it be possible to add a one-line check
> for that the user has permission to do file.io <http://file.io/>
> <http://file.io <http://file.io/>> before calling File.Exists
> (the alternative , of catching and ignoring the
> AccessControlException is ugly!). The hardest part of this is
> that the check would need to be added at multiple points in the
> Drools source code.
>
>
> Any thoughts / comments/ suggestions?
>
> Paul
>
> www.firstpartners.net/blog <http://www.firstpartners.net/blog>
> <http://www.firstpartners.net/blog>
>
>
>
> WARNING: java.security.AccessControlException: access denied
> (java.io.FilePermission /home/paul/drools.rulebase.conf read)
> 13-May-2009 09:04:16
> com.google.apphosting.utils.jetty.JettyLogger warn
> WARNING: Nested in javax.servlet.ServletException:
> java.security.AccessControlException: access denied
> (java.io.FilePermission /home/paul/drools.rulebase.conf read):
> java.security.AccessControlException: access denied
> (java.io.FilePermission /home/paul/drools.rulebase.conf read)
> at
> java.security.AccessControlContext.checkPermission(AccessControlContext.java:323)
> at
> java.security.AccessController.checkPermission(AccessController.java:546)
> at
> java.lang.SecurityManager.checkPermission(SecurityManager.java:532)
> at
> com.google.appengine.tools.development.DevAppServerFactory$CustomSecurityManager.checkPermission(DevAppServerFactory.java:76)
> at java.lang.SecurityManager.checkRead(SecurityManager.java:871)
> at java.io.File.exists(File.java:731)
> at
> org.drools.util.ChainedProperties.loadProperties(ChainedProperties.java:225)
> at
> org.drools.util.ChainedProperties.<init>(ChainedProperties.java:59)
> at
> org.drools.util.ChainedProperties.<init>(ChainedProperties.java:31)
> at
> org.drools.util.ChainedProperties.<init>(ChainedProperties.java:25)
> at
> org.drools.RuleBaseConfiguration.init(RuleBaseConfiguration.java:174)
> at
> org.drools.RuleBaseConfiguration.<init>(RuleBaseConfiguration.java:133)
> at
> org.drools.common.AbstractRuleBase.<init>(AbstractRuleBase.java:147)
> at
> org.drools.reteoo.ReteooRuleBase.<init>(ReteooRuleBase.java:124)
> at
> org.drools.reteoo.ReteooRuleBase.<init>(ReteooRuleBase.java:101)
> at
> org.drools.RuleBaseFactory.newRuleBase(RuleBaseFactory.java:57)
> at
> org.drools.RuleBaseFactory.newRuleBase(RuleBaseFactory.java:38)
> at
> net.firstpartners.drools.RuleRunner.loadRules(RuleRunner.java:39)
> at
> net.firstpartners.drools.RuleRunner.runStatelessRules(RuleRunner.java:167)
> at net.firstpartners.rp2.rp2Servlet.callRules(rp2Servlet.java:96)
> at net.firstpartners.rp2.rp2Servlet.service(rp2Servlet.java:137)
> at javax.servlet.http.HttpServlet.service(HttpServlet.java:806)
> at
> org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:487)
> at
> org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1093)
> at
> com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43)
> at
> org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1084)
> at
> org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:360)
> at
> org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
> at
> org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:181)
> at
> org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:712)
> at
> org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:405)
> at
> com.google.apphosting.utils.jetty.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java:54)
> at
> org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:139)
> at
> com.google.appengine.tools.development.JettyContainerService$ApiProxyHandler.handle(JettyContainerService.java:306)
> at
> org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:139)
> at org.mortbay.jetty.Server.handle(Server.java:313)
> at
> org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:506)
> at
> org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:830)
> at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:514)
> at
> org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:211)
> at
> org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:381)
> at
> org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:396)
> at
> org.mortbay.thread.BoundedThreadPool$PoolThread.run(BoundedThreadPool.java:442)
>
>
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